MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; Tianjin Key Laboratory of Environmental Technology for Complex Trans-Media Pollution, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; Tianjin Key Laboratory of Urban Ecology Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; Tianjin Advanced Water Treatment Technology International Joint Research Center, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; Tianjin Key Laboratory of Environmental Technology for Complex Trans-Media Pollution, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; Tianjin Key Laboratory of Urban Ecology Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; Tianjin Advanced Water Treatment Technology International Joint Research Center, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
Sci Total Environ. 2019 Dec 20;697:134173. doi: 10.1016/j.scitotenv.2019.134173. Epub 2019 Aug 28.
Low pH requirement is one of the biggest limitations of the application of traditional Fenton and electro-Fenton (EF) process because Fe/Fe would precipitate at high pH. In this study, a flow-through EF system operated in batch recirculation mode was constructed. Nitrilotriacetic acid (NTA) was used as a chelating agent in the EF system (NTA/EF) to keep iron soluble at high pH values, producing OH by reaction of HO generated in situ with FeNTA that obtained by the reduction of FeNTA at the cathode. This flow-through NTA/EF system accelerated the mass transfer of target molecules to the electrode surface and showed high efficiency for phenol removal at pH 5-8 with rate constants (k) at around 0.26 min, higher than that of the batch test (k = 0.15 min) and EF process without NTA (k = 0.16 min). The influences of aeration rate, current, flow rate, Fe dose, the ratio of NTA to Fe, pH, and initial phenol concentration on the phenol removal were investigated. The system could be used for at least 3 times for phenol removal without obvious efficiency decline. The flow-through NTA/EF system is promising for the removal of organic contaminants in a wide pH range.
低 pH 值要求是传统芬顿和电芬顿（EF）工艺应用的最大限制之一，因为 Fe/Fe 在高 pH 值下会沉淀。在这项研究中，构建了一种在批循环模式下运行的流通式 EF 系统。在 EF 系统（NTA/EF）中使用氮三乙酸（NTA）作为螯合剂，以保持铁在高 pH 值下的可溶性，通过原位生成的 HO 与通过阴极还原获得的 FeNTA 反应生成 OH。这种流通式 NTA/EF 系统加速了目标分子向电极表面的传质，并在 pH 值为 5-8 时对苯酚去除表现出高效，速率常数（k）约为 0.26 min，高于批试验（k=0.15 min）和没有 NTA 的 EF 工艺（k=0.16 min）。考察了曝气速率、电流、流速、Fe 剂量、NTA 与 Fe 的比例、pH 值和初始苯酚浓度对苯酚去除的影响。该系统可至少用于 3 次苯酚去除，而效率无明显下降。流通式 NTA/EF 系统有望在较宽的 pH 值范围内去除有机污染物。
